Commissioning a control system is important for verifying the correct installation of field devices and their interface to the control system. Commissioning includes tests to exercise electrical and instrumentation (E&I) equipment (e.g., field devices) to check that all components, including hardware, wiring, and software function correctly and signals display accurately on panel readouts and human-machine interfaces (HMIs). E&I equipment includes sensors (inputs), actuators (outputs), motor control, interlocks, alarms, safety overrides, and the like. Where applicable, the testing of entities that form a signal path from the field to the control system and back to the field is performed together in what is designated as a loop or a control loop. Generally, instrumentation, motor control centers (MCCs), alarms, and interlocks are tested and validated as part of the commissioning process. These tests are often referred to as function tests or functional tests.
Commissioning an industrial facility may also include tests to visually inspect components and/or verify documentation, which are separate from the tests that comprise functional tests.
Testing of instrumentation typically requires manipulation of a signal associated with an E&I device. Generally, an input, as used herein, comprises a signal that is generated by an E&I (i.e., field) device and received by a control system. Conversely, an output, as used herein, comprises a signal that is generated by the control system and causes a response in an E&I device. Therefore, input means manipulating the signal from the field and for outputs this means manipulating the signal from the control system typically from an HMI workstation. For example, to carry out a simple test on an input, a technician would go into the field and manipulate the input using a calibration device such as a signal simulator to vary the input over the device's range (i.e. interject a 4-20 mA or for a digital fieldbus simply use an interfacial device as the calibration device to command the signal to vary over its range). Simultaneously, another technician will be in the control room, which is physically located away from the field device, to see how the input signal is displayed on an HMI screen. The technician in the field will set the input to some value and communicate back to the control room to ask the other technician to validate that the signal is displayed correctly. If it is correctly displayed, then the signal is wired correctly from the field to the control system, which generally includes from the field to an I/O module, from the I/O module to the controller, from the controller to the supervisory network. It also validates that the software has scaled and tagged the signal correctly.
For a set of E&I devices that constitute a loop, manipulation may also be done on one of the devices to see if the proper response is achieved by the other components that comprise the loop.
FIG. 1 illustrates the current method to perform function tests of control system inputs and outputs. Generally, the current method of performing function tests of a control system is described in an IEC Standard, IEC 62382 Electrical and Instrumentation Loop Check. 2012, Edition 2.0. Switzerland, IEC Central Office, incorporated by reference. As shown in FIG. 1, currently, to perform function tests, a first technician (Technician A) 102 is typically positioned in a control room 104 at a workstation 106 such as a PC based workstation that acts as a human to machine interface (HMI), while a second technician (Technician B) 108 is positioned at a field device 110. Field devices 110 may comprise, for example, devices such as level transmitters, alarms, and the like that create analog or digital signals that are received by a controller 116. Field devices 110 may also comprise, for example, devices that receive analog or digital signals that originate from the controller 116 where such analog or digital signals may comprise control signals to motorized valves, speed signals, start and shut-down signals, and the like. Field devices 110 may also comprise, for example, motors and/or motor control centers, and the like. In the exemplary case of FIG. 1, the field device 110 being tested is a flow transmitter (FT 321) for measuring flow through a pipe, which provides an analog input to the control system 114. Other field devices 110 shown in FIG. 1 include a modulating valve that is positioned by an analog output from the control system 114. Another field device shown in FIG. 1 is a motor, which may interface to a motor control center (MCC) (which may also be considered a field device 110) and may require analog and/or digital inputs and outputs from the control system 114 to, for example, start or stop the motor, control motor speed (if variable speed), provide feedback as to the status of the motor, and the like.
The two technicians, Technician A 102 and Technician B 108 communicate during the test using a communication device 112 such as a walkie-talkie, cell phone, phone system, intercom, etc. The exemplary control system 114 of FIG. 1 is comprised of an input/output (I/O) network that may include as components the controller 116, an I/O module 118, and communications connections 120, which may be wired (including fiber optics), wireless, or combinations thereof that communicatively couples the various components. Various control protocols such as ProfiBus, ModBus, etc. can be used for transmitting data and/or instructions among the components.
As shown in FIG. 1, Technician B 108 uses a calibration device 122 to inject a signal into the control system 114, where the signal is to simulate a signal from an analog input field device 110 such as FT 321. Alternatively, the Technician B 108 could cause the field device 110 itself to inject the signal into the control system 114. For example, if the field device 110 was a pressure transmitter having a diaphragm, the Technician B 108 could manually put pressure on the diaphragm. For example purposes, assume that the expected input signal from field device 110 is a 4-20 mA analog signal, where the 4-20 mA signal represents the flow rate from 0 to 100 standard cubic feet per minute (SCFM). It is to be appreciated that a 4-20 mA signal is for example purposes only and the analog input signal may be a current input of any range or a voltage input of any range. Returning to the example, assume that Technician B 108 injects a 12 mA signal into the control system 114 using the calibration device 122. The 12 mA signal is representative of a signal that would be generated by field device 110 FT 321 during operation. The signal is received at the I/O module 118 (where it may or may not be scaled), and then is transmitted from the I/O module 118 to the controller 116, where it may undergo further processing and/or scaling. The controller 116 is communicatively coupled with the workstation 106, which has a HMI such as a graphical user interface (GUI). Technician A 102 monitors the workstation 106. After injecting the 12 mA signal into the control system 114, Technician B 108 will contact Technician A 102 over the communication device 112 and ask Technician A 102 what value Technician A 102 is seeing on the HMI. In this example, Technician B 108 would expect Technician A 102 to see a value of approximately 60 SCFM for the field device 110 FT321. Technician A 102 watches the HMI of the workstation 106 to see that the displayed value is correct and that it represents the scaled value for field device 110 FT321 in proper engineering units. Generally, Technician A 102 would then record the result of the test in a spreadsheet manually.
The purpose of the exemplary exercise represented by FIG. 1 is to validate that the signal entered from the field (i.e., 12 mA) gets processed throughout the control system 114 to represent the correct value and engineering units for field device 110 FT321. This test also checks all wiring/communications from the field device 110 FT321 to the I/O module 118, to the controller 116, to the workstation 106. This also checks that any analog to digital conversion done by the control system 114 is correct and the final value displayed at the workstation 106 is scaled correctly. Alarm checking may also be performed in a similar manner.
The communication between Technician B 108 and Technician A 102 as shown in FIG. 1, as well as manual recordation of results, may slow the testing progress and may lead to errors. Furthermore, as illustrated in FIG. 1, such testing requires at least two technicians, Technician A 102 and Technician B 108.
A need, therefore, exists for methods and systems that overcome challenges in the art, some of which are described above.